a. For healthy individuals, cleared by a physician for regular physical activity, are there any health risks for creatine use?

Creatine is one of the most researched supplements on the market. There have been negative anecdotal claims regarding creatine supplementation as an unsafe supplement that can cause gastrointestinal problems, muscle cramping, and have negative effects on liver and kidney functions. A review study by Kim et al. looking at past studies’ findings on the safety of creatine supplementation concluded that a supplementation of 20g/day to have no effect on liver or kidney function. A 2008 study conducted by Cancela et al. looked at creatine monohydrate supplementation on football players over an 8-week period. Blood results showed that creatine supplementation had no adverse effects on blood and urinary clinical health markers, but that it may play a role in improving the efficiency for ATP resynthesis as well as slightly influencing glucoregulation. Although creatine supplementation appears to be safe in healthy populations, long-term administration in various populations can have different effects.

b. Based on the literature, what type of physical activities might benefit from creatine supplementation/what type of activities might creatine have no effect OR worsen performance?

Faraji et al. examined a group of 21 year old collegiate males to see if six days of creatine supplementation would improve their athletic performance in the 100 and 200 meter sprint. They found a significant increase in 100m time from the creatine group, but did not find a significant increase in the 200 meter time. They concluded that the 200 meter time did not improve as much due to the participants not having enough time to develop the conditioning to run the longer distance.

Rawson and Volek found that creatine supplementation short-term weightlifting performance and training volume which can allow for a greater overload during training efforts. They also mention that elevated intramuscular creatine can enhance glycogen levels.

The findings in both these studies support the claim that creatine supplementation can improve athletic performance. Looking at the Faraji and Volek studies as a whole points to creatine supplementation mainly improving activities that rely heavily on the ATP-PC system as its source of energy. Someone who competes in powerlifting or football will benefit much more from creatine supplementation than someone participating in a high endurance event such as an ironman marathon.